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authorAndrei Vagin <avagin@openvz.org>2018-04-10 16:31:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-11 10:28:33 -0700
commitf66406638fffe874c56e7e41106167c5235f251e (patch)
tree320407bf48534b78fcf346711e87b3d5131f6fda /fs/proc
parentd1be35cb6f96975d792a1535d3fe9b75239065ee (diff)
proc: replace seq_printf on seq_putc to speed up /proc/pid/smaps
seq_putc() works much faster than seq_printf() == Before patch == $ time python test_smaps.py real 0m3.828s user 0m0.413s sys 0m3.408s == After patch == $ time python test_smaps.py real 0m3.405s user 0m0.401s sys 0m3.003s == Before patch == - 75.51% 4.62% python [kernel.kallsyms] [k] show_smap.isra.33 - 70.88% show_smap.isra.33 + 24.82% seq_put_decimal_ull_aligned + 19.78% __walk_page_range + 12.74% seq_printf + 11.08% show_map_vma.isra.23 + 1.68% seq_puts == After patch == - 69.16% 5.70% python [kernel.kallsyms] [k] show_smap.isra.33 - 63.46% show_smap.isra.33 + 25.98% seq_put_decimal_ull_aligned + 20.90% __walk_page_range + 12.60% show_map_vma.isra.23 1.56% seq_putc + 1.55% seq_puts Link: http://lkml.kernel.org/r/20180212074931.7227-2-avagin@openvz.org Signed-off-by: Andrei Vagin <avagin@openvz.org> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/task_mmu.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3026feda0432..65ae54659833 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -688,8 +688,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
if (!mnemonics[i][0])
continue;
if (vma->vm_flags & (1UL << i)) {
- seq_printf(m, "%c%c ",
- mnemonics[i][0], mnemonics[i][1]);
+ seq_putc(m, mnemonics[i][0]);
+ seq_putc(m, mnemonics[i][1]);
+ seq_putc(m, ' ');
}
}
seq_putc(m, '\n');